Azo dyestuff and its production



' Patented Sept; 3,1935 I UNITED STAT -s IPAITEQNT: OFFICE AZO DYESMTUFFAND ITS PRODUCTION Norman Hulton Haddock Prestwich, and CliffordPrestwich Park North,

Paine, Handforth, England, assignors to Imperial Chemical IndustriesLimited, a corporation of Great Britain No Draiiving.- Application April6, 1932, Serial No. 603,,682. In Great Britain April 29, 1931 25 Claims.

The present invention relates to organic. compounds and moreparticularly refers to the manufacture of azo dyestuffs, and theproducts resulting therefrom.

s The object of this. invention is to produce a new azo dyestufi whichmay be made insoluble by treatment on the fibre with dilute mineralacids;

Further objects are to produce azo dyestuffs which are fast to washing,to produceazo dye.- l-p stuffs having substituted in the end componentthe carboxyl group, to produce azo dyestuffs'in which the carboxyl groupmay be eliminated by treatment with dilute mineral acids, and to produceazo dyestuffs whose solubility depend upon 15 the presence of thecarboxylgroup in the end component and which are made insoluble by theelimination of this carboxyl group. Additional objects will appearhereinafter.

, These objects are attained according to the 20 present inventionwherein aromatic. mono-' and di-amino compounds, which may contain oneor more azo groups, are 'diazotized and coupled with anortho-amino-aryl-thioglycollic acid'possessing a free coupling position.The product re- 25 sulting therefrom may be applied to the fibre andtreated thereon with a dilute mineral acid.

1 The invention may be more fully understood by a consideration of thefollowing examples. -It

is to be understood that these examples are in- 30 tended merely toillustrate the specific methods by means of which the products of thepresent invention may be obtained and are not to be construed aslimiting the spirit and scope of the invention.

Example I were diazotized in the usual way. I The solution of diazocompound thus. produced was added slowly to an ice-cold solution of 25.5parts of the sodium salt of 1-amino2-naphthyl-tlnogly- Example IIEighteen and four-tenths (182) parts of benzidine were tetrazotized inthe customary manner. The resulting tetrazo-solution was gradu- 5 allyadded to an ice-cold solution of 51parts of the Ten and seven-tenths(10,7) parts of o-toluidin'e 'for 2 hours.

sodium s'alt'of 1-amino-2-naphthyl thioglycollic acid and 28 partsof'sodium acetate crystals in 300 parts of water. After 2 hours thereaction mixturewas made neutral to litmus by the addition of aqueoussodium carbonate, the tempera- 5 ture was raised. to 25 C. and themixture was stirred for a further 20 hours to complete the reaction. Thenew dyestufi was then isolated by the addition of salt, followed byfiltration. The

product was water soluble, dyed cotton bluish-' 10 red shades from analkaline bath, and was con-' verted on the fibre, to an insoluble,yellowish-red lactam by warming the dyed cotton to 70 C. in Ahydrochloric acid, followed by rinsing in dilute alkali and finallyrinsing in water. 5

Example Ill Twenty-one and six-tenths (21.6) parts of 4:4-diamino-diphenyl-sulfide were tetrazotized in the customary manner. Theresulting. tetrazo solution-was gradually added to an ice-cold solutionof 25.5 parts of the sodium salt of l-amino- 2 naphthyl-thioglycollicacid and-28 parts of sodium acetate crystals in 300 parts of water. a

After stirring for .two hours a solution of 31.5

parts of 2-phenylamino-3-naphthol-6-su1fonic A acid and 30 parts ofanhydrous sodium carbonate -in 250 parts of Water was added to thereaction mixture, giving finally an alkaline reaction to brilliantyellow paper. After stirring for one 30 more hour the combination washeated to 80 C. and isolated by the addition of a little common salt;followed by filtration' The new dyestufi' dyed cotton in bluish-brownshades from an alkaline bath. By warming the dyed material in dilutemineral acids, followed by rinsing in dilute sodium carbonate, thedyeing became yellow- -brownin shade and faster to washing.

Example Fl? f One hundred fifty (150) parts of p-aminoacetanilide werediazotized and the resulting diazo solution was made neutral to Congored paper bythe additionof sodium acetate crystals.

- A solution of 23.5 parts of the sodium salt ofl-naphthyl'amine-T-sulfonic acid in 300 parts of water was graduallyadded during one hour.- After stirring for 12 hours the mono-azocompound was filtered off, dissolved in 30.0 parts. of 10% sodiumhydroxide and boiled under reflux The hydrolyzed product wasprecipitated by the addition of 310 parts of 10% hyv drochloric acid,filtered, and finally re-dissolved in500 parts of water and 10.6 partsof anhydrous then made alkaline sodium carbonate. The solution was thentetrazotized by the addition of '70 parts of 20% aqueous sodium nitrite,followed by 50 parts of hydrochloric acid (sp. gr. 1.16).Tetrazotization was allowed to continue for 3 hours at 150 and theresulting suspension was slowly passed into a solution of 51 parts ofthe sodium salt of 1-amino-2-naphthyl-thioglycollic acid and 35 parts ofsodium acetate crystals in 400 parts of water. Combination wassubstantially completed in 2 hours and the coupling solution was tobrilliant yellow paper by the addition of 50 parts of anhydrous sodiumcarbonate, common salt added and the precipitated new tris-azo dyestufffiltered off.

It dyed cotton from an alkaline bath in bluegrey to black shades and bywarming the dyed material in dilute mineral acids, followed by rinsingin dilute sodium carbonate, it became faster to washing.

were diazotized in the customary manner and the resulting diaz-osolution was gradually added to an ice-cold solution of 15.9 parts ofl-amino- S-naphthol in 200 parts of water and 40 parts of 30% sodiumhydroxide. The combination was rapid and after half an hour the mono-azocompound was isolated by the addition of common salt and filtered off.The precipitate was resuspended in 1000 parts of water and dissolved bythe addition of 13.3 parts of 30% sodium hydroxide. 35 parts of 20%aqueous sodium nitrite were then added, followed by 30 parts ofhydrochloric acid (sp. gr. 1.16), the temperature being maintained at10-15 C. for 6 hours. The resulting diazo-azo compound was passedgradually into'a solution of 25.5 parts of the sodium salt ofl-amino-2-naphthyl-thioglycollic acid and 25 parts of water at atemperature of 0-5 C. After stirring for two more hours combination wassubstantially completed. The reaction mixture was made alkaline tobrilliant yellow paper by the addition of sodium carbonate, heated toC., the new-formed dyestufi precipitated by the addition of a littlecommon salt and filtered ofi. It dyed cotton, from an alkaline bath inbluishgrey to black shades. By treating the dyeings with warm dilutemineral acids, followed by rinsing in dilute sodium carbonate, they were rendered faster to washing and somewhat redder in shade.

In the above examples, 1-ar'nino-2-phenylthioglycollic acid may besubstituted for l-amino- 2-naphthyl-thioglycollic acid with verysatisfactory results. The ortho-amino-aryl-thioglycollic acid used inaccordance with the present invention may have substituted thereonalkyl, halogen, methoxy, and similar groups. These groups must notoccupy positions in which coupling will take place. Not only may aminocompounds be diazotized and coupled with the orthoanino-aryl-thioglycollic acid but diamino compounds may be tetrazotizedand coupled. with the same component,

The products produced by the process of the present inventionmay berepresented by the following formulas in which A represents an mlamine;M stands for the middle coupling components, capable of rediazotizing; Drepresents tetrazctizable diamine; 1! represents the end comformula ofthe dyestufi on the ponent which is a single copulatory compound; standsfor diazotized and coupled with:

Monoazo A-E The products of the present invention may be applied to theproduction of fast colors on either animal or vegetable fibres(including derived fibres such as artificial'silks from regeneratedcellulose or from cellulose esters or others).

These products are easily applied to the fibres and after being appliedthereto are rendered insoluble by treatment with a dilute mineral acid,resulting in a color which is exceedingly fast to washing. This is avery effective method of producing an insoluble dye on the fibre and forthis reason is very valuable from a commercial standpoint.

Without any intention to limit this invention, the following theory isadvanced to explain the observed properties of behavior of the newdyestufis. To consider, for instance, the product of Example 1, when itis isolated in the form of its sodium salt it most probably correspondsto the following formula:

Because of the presence of the COONa group,

.ment with a mineral acid, such as dilute hydrochloric acid, andwarming, the compound apparently first becomes converted into the freeacid, and then splits off water to form a thiazine ring. This process isknown as lactamization, and the compound produced is a lactam. The

fiber most probably corresponds to the following:

Since the lactam form is insoluble in water, the dyeing becomes fast towashing.

The lactam form, as well as the sodium or other salt of the dyestufiunder discussion, may be considered as special'forms of a compound whichin the form of its hypothetical free acid may be represented by theformula SCHr'C O OH tized ammo compound,

.than one azo group,

free acid, the lactam form, as well as the alkali-metal salt forms;

cover generically the fined in the appended claims.

We claim:

1. A process for the compounds which comprises coupling a diazowhich maycontain more than one azo group, glycollic acid having a free coupling.position.

2. A process for the manufacture of new azo compounds which comprisescoupling a diazotized amino compound, which may contain more with ano-amino-aryl-thioglycollic acid having a free coupling position, but notcontaining sulfonic acid or additional carboxyl groups. v

3. A process for the manufacture of new azo compounds which comprisescoupling a diazotized amino compound, which maycontain more than one azogroup, with 1-amino-2 phenyl-thioglycollic acid.

boxyl groups.

5. A process for the manufacture of new azocompounds which comprisescoupling a diazotized amino compound, which may contain more than oneazo group, with 1-amino-2-naphthyl-thioglycollic acid. 1

6. A process for'the manufacture of new azo compounds which comprisescoupling a diazotized amino compound, which may contain more than oneazogroup, with al-amino-Z-naphthylthioglycollic acid having a, freecoupling position,

but not containing sulfonic acid or additional carboxyl groups. i

7. A process for themanufacture of new azo compounds which comprisescoupling a diazotized member selected from the group consisting ofo-toluidine, benzidine, ,4 4'-diamino-diphenylsulfide, 4-l'-diamino-7'-sulfonic acid-benzeneazo-naphthalene, andbenzene-azo-4'-amino-8'- naphthol with 1-amino-2-naphthyl-thioglycollicacid.

8. A process for the manufacture of new azo compounds which comprisescoupling diazotized o toluidine with '1-amino-2-naphthyl-thioglycollicacid. V

l 9. A process for the manufacture of new azo compounds which comprisescoupling diazotized o-toluiolinev with a1-amino-2-naphtliyl-thioglycollic acidhaving a free 'coupling position,but not containing s'ulfonic acid or additional carboxyl groups.

10. Organic compounds. containing at least one azo group and having asan end component the alkali-metal salt of an o-amino-aryl-thioglycollicacid. l

11'. Organic compounds containing at least one azo group and having asanend component the alkali-metal 'salt of leamino-2-phenyl-thioglycolli'cacid. v

12. Organic compounds containing at least one azo group and having as anend component the alkali-metal salt Of 1-aIfiino-2-naphth 1 y ol licacid. 9

. and R1 represents with an o.-amino-aryl-thio- 17. A dyestufi a the g 313. Azo compounds, adapted to be rendered insoluble by warming in dilutemineral acids, and having in the form of their hypothetical free thefollowing general formula:

SCHaCOOH ble amine containing no water-solubilizing groups,

the aryl residue of an o-aminoaryl-thioglycollic acid.

14. A20 compounds, adapted to be rendered insoluble by warmingin'dilute. mineral acids, and

having in the form of their hypothetical free acid the following generalformula:

, having in the form of their hypothetical free acids the followinggeneral formula:

I somooon RN==N-R1 wherein R represents the residue of a diazotizableamine containing no water-solubilizing groups,

and R1 represents the aryl residue of a l-amino-Z-naphthyl-thiogiycollic acid.

16. An azo compound having in the form of its hypothetical free acid thefollowing formula:

S CHzCOOH azo class adapted to dye animal and vegetable flber, saiddyestufi being water-sollible in substance but water-insoluble when dyedon the fiber, said dyestuff comprising in its structure a. plurality ofaryl nuclei joined together by at least one azo bridge and free fromsulfo groups, said dyestuif being characterized by the presence in itsaryl-thioglycollate radical when in substance, and by the presence of alactam radical of the general formula when on the fiber.

18.; A dyestuff of the animal and vegetable azo class adapted to dyefiber, said dyestufi being water-soluble in substance butwater-insoluble when dyed on the fiber, said dyestuff comprising in itsstructure a plurality of aryl nuclei joined structure of an ortho-aminmin its structure when in substance and being convertible when on thefiber into alactam radical of the formula Y NHC O on each end of themolecule.

20. Textile material when dyed with the lactam form of a dyestuff asdefined in claim 1'7.

21. Textile material when dyed with the laetam form of a dyestuff asdefined in claim 18.

22. Textile material when dyed with the lactam form of a dyestufi asdefined in claim 19.

23. A process for dyeing textile material which comprises applyingthereto an aqueous solution of the salt form of a dyestuff as defined inclaim 1'7, and then treating the fiber with a dilute solution of mineralacid whereby to convert the dyestufi on the fiber into a water-insolublelactam form.

24. A process for dyeing textile material which comprises applyingthereto an aqueous solution of the salt form of a dyestuff as defined inclaim 18, and then treating the fiber with a dilute solution of mineralacid whereby to convert the dyestuff on the fiber into a water-insolublelactam form.

25. A process for dyeing textile material which comprises applyingthereto an aqueous solution of the salt form of a dyestuff as defined inclaim 19, and then treating the fiber with a dilute so lution of mineralacid whereby to convert the dyestuff on the fiber into a water-insolublelactam form.

NORMAN HULTON HADDOCK. CLIFFORD PAINE.

